Electrical discharge lamp



Jan. 12, 1960 T. D. WHITENACK, JR 2,

ELECTRICAL DISCHARGE LAMP Filed Jan. 28. 1958 INVENTOR.

TAYLOR D. WHITENACK,JR

ATTOR YS Unite States Patent ELECTRICAL DISCHARGE LAMP Taylor D. Whitenack, Jr., Livingston, N.J., assignor to Eugelhard Industries, Inc.

Application January 28, 1958, Serial No. 711,603

3 Claims. (Cl. 313-318) The present invention deals with an electrical discharge lamp and more particularly with an electrical discharge lamp of the type having hermetically sealed lead-in conductors.

It is known to provide hermetical seals for gas or vapor discharge lamps by fusing a vitreous extension or seal stem to the lamp envelope, the stem containing a leadin conductor in the form of a thin metal strip such as molybdenum foil at least a part of which is embedded vacuum-tightly in the seal stem.

When input leads, especially flexible input leads of the stranded wire type, are connected to the thin strip conductor at the end of the seal stem, there is substantial strain on the lead-in and input connection in handling or operating the lamp. Such strain causes failure of the lead-in and input connection and failure of the lamp unless the seal is adequately protected against strains.

In the past, the strain on the seal input connection has been overcome to some extent by bending the input wire back along the seal stem and tying the input wire to the stem to act as a strain relief, or by cementing the input junction. Neither of these strain reliefs is fully satisfactory either due to a lack of strentgh or because the strains have not been sufliciently overcome.

It is an object of the present invention to provide the seal stem of an electrical discharge lamp with a strain relief means for the lead-in and input junction. It is another object of the present invention to provide an electrical discharge lamp with a means for effecting not only strain relief for the lead-in and input junction, but which also supplements the junction bond. Other objects and advantages of the invention will become apparent from the description hereinafter following and drawings forming a part hereof, in which:

Figure 1 illustrates a side view of an electrical discharge lamp according to the invention,

Figure 2 illustrates a perspective view of a clamp member according to the invention and prior to assembly,

Figure 3 illustrates an enlarged fragmentary view of Figure l, and

Figure 4 illustrates an end view along lines 4-4 of Figure 3.

The invention deals in particular with the combination of an electrical discharge lamp seal member and a clamp means which is positioned on the seal member and provides not only adequate strain relief for the lead-in and input junction of the lamp, but which also supplements the junction bond.

Referring to Figure 1, the lamp according to the invention comprises a light transmissive envelope 1 containing an ionizable atmosphere and spaced electrodes 2 and 3. Extending outwardly of both ends of the envelope are vitreous hermetical seal stems 4 and 5 of substantially cylindrical shape and welded to the envelope. Each seal stem is provided with an electrical conductive lead-in strip 6 and 7, e.g. a thin molybdenum strip, pass- 'ice ing longitudinally through the stem and with at least a portion of each strip being hermetically embedded in the stem. One end 8 and 9 of each strip is connected to an electrode 2 and 3 and the other end 10 and 11 of each strip is connected to a flexible input conductor 12 and 13, e.g. a flexible input conductor of stranded wire.

in order to effect adequate strain relief at the junction of input wire 12 and strip input end 10, also at the junction of input wire 13 and strip lead-in end 11, clamps 14 and 15 are circumferentially secured over the seal stems 4 and 5, respectively, substantially at the free ends thereof, and brought into welded engagement with the above-mentioned junctions.

Figure 2 illustrates a perspective view of one of the clamps 14 and 15 prior to assembly. The clamp comprises a substantially U-shaped strip 16 having mating legs 17 and 18 extending outwardly of a one edge 19 of the U-shaped strip 16, one leg being positioned directly opposite the other on said edge 19. Particularly, the legs extend straight outwardly in parallel from the edge 19 for a portion of their lengths, then inwardly toward each other, and then again straight outwardly in close proximity to each other forming clamp jaws 20 and 21.

On assembly, according to Figure 4, the U-shaped strip is placed over, for example, the seal stem 4 with the ends 10 and 12 being positioned between the jaws 20 and 21. The ends of the U-shaped strip 16 are brought together to form a band, they are then welded together with the excess lengths folded upon themselves as at 23. As a modification, the band 22 can be preformed prior to assembly in lieu of the U-shaped strip. After forming and affixing the band 22, the jaws 20 and 21, and ends of 10 and 12 are welded together forming a secure bond, whereupon any strain on the wire 12 is transmitted directly to the legs 17 and 18 and ring 22 substantially eliminating strain at the junction of the input conductor and the lead-in strip.

Modifications of the invention are contemplated in the scope of the appended claims.

What is claimed is:

1. An electrical discharge lamp comprising a light transmissive envelope, a substantially cylindrical seal stem extending outwardly of the envelope, an electrically conducting strip sealed to and passing longitudinally through the seal stem, clamp means comprising a metal band member circumferentially secured over the seal stem substantially at the free end thereof, mating legs extending outwardly of an edge of the band member, flexible electrical input means having an end thereof connected to an end of the electrically conducting strip, the legs being clamped over and welded to both the electrically conducting strip and the electrical input means.

2. An electrical discharge lamp according to claim 1, wherein said legs are positioned substantially diametrically of said band member.

3. An electrical discharge lamp according to claim 1 wherein said flexible electrical input means is a stranded wire.

with- References Cited in the file of this patent UNITED STATES PATENTS 768,479 OBrien Aug. 23, 1904 1,727,826 Harris Sept. 10, 1929 1,924,036 Harrington Aug. 22, 1933 1,932,018 Hubbell Oct. 24, 1933 2,211,605 Moehler Aug. 13, 1940 2,238,596 Mouromtsefl Apr. 15, 1941 2,515,747 Vaughan July 18, 1950 

